"The representation of a system to study its component parts and their relationships in terms of variable inputs and outputs".
Or "Representation of natural and social systems or processes by devices or models that imitate the behavior of the systems or processes" (UNESCO-UNE, 1983, p.14).
A.G. BARTO describe simulation as follows: "The method used to find the model's global behavior base of knowledge of an initial condition and the locally acting constraints" (1991, p.388).
As observed by F. FRISCHKNECHT and J.P.van GIGCH, simulation is basically the creation of an equivalence relation between objects and adequate symbols (1989, p.243) This is the deeper meaning of "representation ". Adequate symbols must be at least homomorphic. As to "objects", they are normally complex, i.e. include internal relationships and, when useful, external connections.
Simulation models are necessarily dynamic.
"If… a computer is used to generate the model's behavior, we call the process computational simulation" (A.G. BARTO, Ibid). This author discusses simulation either by continuous, or discrete models. However, whatever the method used, the real value of simulation depends on a correct understanding (in relation to the goals of the operator) of the system to be modelled and the nature of the significant data to be obtained; of the satisfactory homomorphism between the conceptual model and those characteristics of the system to be modelled and, finally of the adequate translation to the computer model. If these different conditions are not fulfilled, the well known motto "Garbage in, garbage out" defines the results.
The quality of the results depends, of course of the fitness of the model, i.e. of the validity of the criteria used for its construction, irrespective of the simulation technique applied. In M.SHUBIK's words: "… once the model has been formalized, the insights and errors of its builder will be reflected without question by the simulation" (1967, p. 151).
In any type of simulation, the user of the results to be obtained must remain interactive with the investigator in charge, in order to maintain the relevance of the simulation in relation to the concrete situation.
The main techniques in use are analog and digital. An important variant is aleatory simulation ("Monte Carlo" method), which introduces constructed randomness in the model.
Simulation is generally aimed at prediction of the behavior of the simulated process or system. For a number of practical and conceptual reasons, the results can however never be fully guaranteed.
Apart of prediction R. AXELROD also states the following uses of simulation (1997, p.16-17):
- Performing certain tasks using artificial intelligence, as for example "… medical diagnosis, speech recognition and function optimization…" and "… simulations of task environments can also help design new techniques"
- Training:… "Flight simulators for pilots is an important example of the use of simulation for training"
- Entertainment: as for example "… simulations of completely imaginary worlds"
- Education:… "The primary use of simulation in education is to allow users to learn relationships and principles for themselves"
- Proof: … "CONWAY's Game of life demonstates that extremely complex behavior can result from very simple rules"
- Discovery: … "Using simulation for prediction can help validate or improve the model upon which the simulation is based… and for the discovery of new relationships and principles… "
- 1) General information
- 2) Methodology or model
- 3) Epistemology, ontology and semantics
- 4) Human sciences
- 5) Discipline oriented
To cite this page, please use the following information:
Bertalanffy Center for the Study of Systems Science (2020). Title of the entry. In Charles François (Ed.), International Encyclopedia of Systems and Cybernetics (2). Retrieved from www.systemspedia.org/[full/url]
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